Thursday, December 11, 2008

Breakthroughs in solar power

From Science Daily, here is an impressive new development in photovoltaic power.
Anna Dyson, an architectural scientist from Rensselaer Polytechnic Institute in Troy, New York, is leading the way to make solar energy a real alternative to pollution-emitting fossil fuels. Her system contains rows of thin lenses that track the sun's movement. Sunlight floods each lens and is focused onto a postage-stamp sized, high-tech solar cell. Dyson says, "Really, what we want to do is be capturing and transferring that energy for usable means."
Conventional solar systems are about 14 percent efficient. This system has a combined heat and power efficiency of nearly 80 percent. "What they're doing is very efficiently capturing and transferring that light into electricity and the solar heat into hot water," Dyson explains.

Watching the video, I get the impression these are best suited to large-scale use - office buildings, malls, and such. They have a lot of moving parts, and they can't be cheap to make.

But there's been another breakthrough more likely to show up in your home: researchers are reporting record efficiencies for dye-sensitized solar cells (DSSCs). And although an efficiency of 10% doesn't sound very exciting compared to the 80% Dyson is claiming, or even the 14% achieved by conventional cells, it's a record for DSSCs, which have lots of other advantages. They're cheap to make, can be fashioned into flexible sheeting, and are tough enough to take on the elements without being encased in glass. They also work better in low-light environments. Until recently, these cells topped out at about 7% efficiency; they also degraded quickly with exposure to heat and UV light. The new cells are more stable at high temperatures and retain high output after long hours in direct sunlight.

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